Dr. van Heerden did not hurry his departure from his Staines house. He spent the morning following Oliva's marriage in town, transacting certain important business and making no attempt to conceal his comings and goings, though he knew that he was shadowed. Yet he was well aware that every hour that passed brought danger nearer. He judged (and rightly) that his peril was not to be found in the consequences to his detention of Oliva Cress well.

"I may have a week's grace," he said to Milsom, "and in the space of a week I can do all that I want."

He spent the evening superintending the dismantling of apparatus in the shed, and it was past ten o'clock on Tuesday before he finished.

It was not until he was seated by Milsom's side in the big limousine and the car was running smoothly through Kingston that he made any further reference to the previous afternoon.

"Is Beale content?" he asked.

"Eh?"

Milsom, dozing in the corner of the car, awoke with a start.

"Is Beale content with his prize—and his predicament?" asked van Heerden.

"Well, I guess he should be. That little job brings him a million. He shouldn't worry about anything further."

But van Heerden shook his head.

"I don't think you have things quite right, Milsom," he said. "Beale is a better man than I thought, and knows my mind a little too well. He was astounded when Homo claimed to be a priest—I never saw a man more stunned in my life. He intended the marriage as a bluff to keep me away from the girl. He analysed the situation exactly, for he knew I was after her money, and that she as a woman had no attraction for me. He believed—and there he was justified—that if I could not marry her I had no interest in detaining her, and engaged Homo to follow him around with a special licence. He timed everything too well for my comfort."

Milsom shifted round and peered anxiously at his companion.

"How do you mean?" he asked. "It was only by a fluke that he made it in time."

"That isn't what I mean. It is the fact that he knew that every second was vital, that he guessed I was keen on a quick marriage and that to forestall me he carried his (as he thought) pseudo-clergyman with him so that he need not lose a minute: these are the disturbing factors."

"I don't see it," said Milsom, "the fellow's a crook, all these Yankee detectives are grafters. He saw a chance of a big rake off and took it, fifty-fifty of a million fortune is fine commission!"

"You're wrong. I'd like to think as you do. Man! Can't you see that his every action proves that he knows all about the Green Rust?"

"Eh?"

Milsom sat up.

"How—what makes you say that?"

"It's clear enough. He has already some idea of the scheme. He has been pumping old Heyler; he even secured a sample of the stuff—it was a faulty cultivation, but it might have been enough for him. He surmised that I had a special use for old Millinborn's money and why I was in a hurry to get it."

The silence which followed lasted several minutes.

"Does anybody except Beale know? If you settled him...?"

"We should have to finish him to-night" said van Heerden, "that is what I have been thinking about all day."

Another silence.

"Well, why not?" asked Milsom, "it is all one to me. The stake is worth a little extra risk."

"It must be done before he finds the Paddington place; that is the danger which haunts me." Van Heerden was uneasy, and he had lost the note of calm assurance which ordinarily characterized his speech. "There is sufficient evidence there to spoil everything."

"There is that," breathed Milsom, "it was madness to go on. You have all the stuff you want, you could have closed down the factory a week ago."

"I must have a margin of safety—besides, how could I do anything else? I was nearly broke and any sign of closing down would have brought my hungry workers to Krooman Mansions."

"That's true," agreed the other, "I've had to stall 'em off, but I didn't know that it was because you were broke. It seemed to me just a natural reluctance to part with good money."

Further conversation was arrested by the sudden stoppage of the car. Van Heerden peered through the window ahead and caught a glimpse of a red lamp.

"It is all right," he said, "this must be Putney Common, and I told Gregory to meet me with any news."

A man came into the rays of the head-lamp and passed to the door.

"Well," asked the doctor, "is there any trouble?"

"I saw the green lamp on the bonnet," said Gregory (Milsom no longer wondered how the man had recognized the car from the score of others which pass over the common), "there is no news of importance."

"Where is Beale?"

"At the old man's hotel. He has been there all day."

"Has he made any further visits to the police?"

"He was at Scotland Yard this afternoon."

"And the young lady?"

"One of the waiters at the hotel, a friend of mine, told me that she is much better. She has had two doctors."

"And still lives?" said the cynical Milsom. "That makes four doctors she has seen in two days."

Van Heerden leant out of the car window and lowered his voice.

"The FrÄulein Glaum, you saw her?"

"Yes, I told her that she must not come to your laboratory again until you sent for her. She asked when you leave."

"That she must not know, Gregory—please remember."

He withdrew his head, tapped at the window and the car moved on.

"There's another problem for you, van Heerden," said Milsom with a chuckle.

"What?" demanded the other sharply.

"Hilda Glaum. I've only seen the girl twice or so, but she adores you. What are you going to do with her?"

Van Heerden lit a cigarette, and in the play of the flame Milsom saw him smiling.

"She comes on after me," he said, "by which I mean that I have a place for her in my country, but not——"

"Not the sort of place she expects," finished Milsom bluntly. "You may have trouble there."

"Bah!"

"That's foolish," said Milsom, "the convict establishments of England are filled with men who said 'Bah' when they were warned against jealous women. If," he went on, "if you could eliminate jealousy from the human outfit, you'd have half the prison warders of England unemployed."

"Hilda is a good girl," said the other complacently, "she is also a good German girl, and in Germany women know their place in the system. She will be satisfied with what I give her."

"There aren't any women like that," said Milsom with decision, and the subject dropped.

The car stopped near the Marble Arch to put down Milsom, and van Heerden continued his journey alone, reaching his apartments a little before midnight. As he stepped out of the car a man strolled across the street. It was Beale's watcher. Van Heerden looked round with a smile, realizing the significance of this nonchalant figure, and passed through the lobby and up the stairs.

He had left his lights full on for the benefit of watchers, and the hall-lamp glowed convincingly through the fanlight. Beale's flat was in darkness, and a slip of paper fastened to the door gave his address.

The doctor let himself into his own rooms, closed the door, switched out the light and stepped into his bureau.

"Hello," he said angrily, "what are you doing here?—I told you not to come."

The girl who was sitting at the table and who now rose to meet him was breathless, and he read trouble in her face. He could have read pride there, too, that she had so well served the man whom she idolized as a god.

"I've got him, I've got him, Julius!"

"Got him! Got whom?" he asked, with a frown.

"Beale!" she said eagerly, "the great Beale!"

She gurgled with hysterical laughter.

"He came to me, he was going to arrest me to-night, but I got him."

"Sit down," he said firmly, "and try to be coherent, Hilda. Who came to you?"

"Beale. He came to my boarding-house and wanted to know where you had taken Oliva Cresswell. Have you taken her?" she asked earnestly.

"Go on," he said.

"He came to me full of arrogance and threats. He was going to have me arrested, Julius, because of those letters which I gave you. But I didn't worry about myself, Julius. It was all for you that I thought. The thought that you, my dear, great man, should be put in one of these horrible English prisons—oh, Julius!"

She rose, her eyes filled with tears, but he stood over her, laid his hands on her shoulders and pressed her back.

"Now, now. You must tell me everything. This is very serious. What happened then?"

"He wanted me to take him to one of the places."

"One of what places?" he asked quickly.

"I don't know. He only said that he knew that you had other houses—I don't even know that he said that, but that was the impression that he gave me, that he knew you were to be found somewhere."

"Go on," said the doctor.

"And so I thought and I thought," said the girl, her hands clasped in front of her, her eyes looking up into his, "and I prayed God would give me some idea to help you. And then the scheme came to me, Julius. I said I would lead him to you."

"You said you would lead him to me?" he said steadily, "and where did you lead him?"

"To the factory in Paddington," she said.

"There!" he stared at her.

"Wait, wait, wait!" she said, "oh, please don't blame me! I took him into the passage with the doors. I borrowed his light, and after we had passed and locked the second door I slipped through the third and slammed it in his face."

"Then——"

"He is there! Caught! Oh, Julius, did I do well? Please don't be angry with me! I was so afraid for you!"

"How long have you been here?" he asked.

"Not ten minutes, perhaps five minutes, I don't know. I have no knowledge of time. I came straight back to see you."

He stood by the table, gnawing his finger, his head bowed in concentrated thought.

"There, of all places!" he muttered; "there, of all places!"

"Oh, Julius, I did my best," she said tearfully.

He looked down at her with a little sneer.

"Of course you did your best. You're a woman and you haven't brains."

"I thought——"

"You thought!" he sneered. "Who told you you could think? You fool! Don't you know it was a bluff, that he could no more arrest me than I could arrest him? Don't you realize—did he know you were in the habit of coming here?"

She nodded.

"I thought so," said van Heerden with a bitter laugh. "He knows you are in love with me and he played upon your fears. You poor little fool! Don't cry or I shall do something unpleasant. There, there. Help yourself to some wine, you'll find it in the tantalus."

He strode up and down the room.

"There's nothing to be done but to settle accounts with Mr. Beale," he said grimly. "Do you think he was watched?"

"Oh no, no, Julius"—she checked her sobs—"I was so careful."

She gave him a description of the journey and the precautions she had taken.

"Well, perhaps you're not such a fool after all."

He unlocked a drawer in his desk and took out a long-barrelled Browning pistol, withdrew the magazine from the butt, examined and replaced it, and slipped back the cover.

"Yes, I think I must settle accounts with this gentleman, but I don't want to use this," he added thoughtfully, as he pushed up the safety-catch and dropped the weapon in his pocket; "we might be able to gas him. Anyway, you can do no more good or harm," he said cynically.

She was speechless, her hands, clasped tightly at her breast, covered a damp ball of handkerchief, and her tear-stained face was upturned to his.

"Now, dry your face." He stooped and kissed her lightly on the cheek. "Perhaps what you have done is the best after all. Who knows? Anyway," he said, speaking his thoughts aloud, "Beale knows about the Green Rust and it can't be very long before I have to go to earth, but only for a little time, my Hilda." He smiled, showing his white teeth, but it was not a pleasant smile, "only for a little time, and then," he threw up his arms, "we shall be rich beyond the dreams of Frankfurt."

"You will succeed, I know you will succeed, Julius," she breathed, "if I could only help you! If you would only tell me what you are doing! What is the Green Rust? Is it some wonderful new explosive?"

"Dry your face and go home," he said shortly, "you will find a detective outside the door watching you, but I do not think he will follow you."

He dismissed the girl and followed her after an interval of time, striding boldly past the shadow and gaining the cab-stand in Shaftesbury Avenue without, so far as he could see, being followed. But he dismissed the cab in the neighbourhood of Baker Street and continued his journey on foot. He opened the little door leading into the yard but did not follow the same direction as the girl had led Stanford Beale. It was through another door that he entered the vault, which at one time had been the innocent repository of bubbling life and was now the factory where men worked diligently for the destruction of their fellows.